1. Field of the Invention
The present invention relates to carbapenem compounds which have excellent antibiotic activity and a broad antibiotic spectrum. More particularly, the present invention relates to novel carbapenem derivatives having a substituted imidazo[5,1-b]thiazole group at the 2-position on the carbapenem ring, or a salt thereof.
2. Related Art
Carbapenem derivatives have potent antibiotic activity and a broad antibiotic spectrum and thus have been energetically studied as a highly useful β-lactam agent, and Imipenem, Panipenem, and Meropenem have already been clinically used.
At the present time, however, both Imipenem and Panipenem, are used as a mixture due to instability against renal dehydropeptidase-1 (hereinafter referred to as “DHP-1”) in the case of Imipenem and in order to reduce nephrotoxicity in the case of Panipenem. On the other hand, Meropenem, by virtue of the presence of a methyl group at the 1β-position, has increased stability to DHP-1 and thus can be used alone. The stability of Meropenem to DHP-1, however, is still unsatisfactory. Further, antibiotic activities against methicillin resistant Staphylococcus aureus (hereinafter referred to as “MRSA”) which has recently caused serious clinical problems, as well as against penicillin resistant Streptococcus pneumoneae (hereinafter referred to as “PRSP”), resistant Pseudomonas aeruginosa, enterococci, and Influenzavirus, are not always satisfactory. Drugs effective for these bacteria which induce infectious diseases have been dedired in the art.
For example, carbapenem derivatives in which a carbon atom on an imidazo[5,1-b]thiazole group is attached to the 2-position of the carbapenem ring are disclosed in WO 98/32760 and WO 00/06581.